Signalling adjustments to direct and indirect environmental effects on signal perception in meerkats

The efficiency of communication between animals is determined by the perception range of signals. With changes in the environment, signal transmission between a sender and a receiver can be affected both directly, where the signal’s propagation quality itself is affected, and indirectly, where for example the spacing between signaller and receiver is impacted. Here we investigated how meerkats (Suricata suricatta) in the Kalahari Desert adjust to these challenges in the context of maintaining group cohesion through contact calls. We found that meerkats changed their calling rate when signal transmission was affected indirectly due to increased dispersion of group members as during a drought, but not under typical wet conditions, when signal transmission was directly affected due to higher vegetation density. Instead under these wetter conditions, meerkats remained within proximity to each other. Overall, both direct and indirect environmental effects on signal perception resulted in an increased probability of groups splitting. In conclusion, we provide evidence that social animals can flexibly adjust their vocal coordination behaviour to cope with direct and indirect effects of the environment on signal perception, but that these adjustments have limitations.

动物间通信的效率由信号的感知范围决定。随着环境变化，信号发送者与接收者之间的信号传输会受到两类影响：直接影响指信号传播质量本身受干扰，间接影响则例如改变信号发送者与接收者之间的间距。本研究聚焦喀拉哈里沙漠的狐獴（Suricata suricatta），探讨它们如何通过联络叫声维持群体凝聚力，以此应对上述信号传输挑战。研究发现，当群体成员因干旱等因素分散程度加剧，致使信号传输受到间接干扰时，狐獴会调整其鸣叫频率；而在典型湿润环境中，植被密度更高导致信号传输受直接干扰时，狐獴并未调整鸣叫频率，反而会主动维持个体间的近距离接触。总体而言，环境对信号感知的直接与间接影响，均会提升群体分裂的概率。综上，本研究证实：社会性动物可灵活调整其发声协调行为，以应对环境对信号感知造成的直接与间接影响，但这类调整存在一定局限性。